Reformation Sunday, celebrated every year on the last Sunday of October, is the anniversary of the start of the Protestant Reformation, when, on October 31, 1517, Martin Luther penned his Ninety-Five Theses and nailed it to the Castle Church door in Wittenberg. One of Luther's Ninety-Five Theses simply declares, “The Church's true treasure is the gospel of Jesus Christ.” Celebrate the day with these songs showcasing each of the Five Solas of the Reformation, or use them as a guide for your Reformation Sunday worship set.